Electric fuse



A. W. STEELE.

ELECTRIC FUSE.

APPLICATION FILED IIIAY24, I9I9.

1,335,404. Patented Mar. 30, 1920.

INVENTOR MN .Sm

Kmmm.

ATTORNEYS UNITED s'rn'rEs PATENT oEEicE.

ARCI-IIE W. STEELE, OF BLGOIVIFIELD, NEW JERSEY, ASSIGNOR TO 'WILFORD J. HAWKINS, 0F MONTCLAIR, NEW JERSEY.

ELECTRIC FUSE.

Application filed May 24, 1919.

To all whom t may concern Be it known that I, ARGHIE W. STEELE, a subject of the King of Great Britain, resid ing at Bloomfield, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Electricl Fuses; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to electric fuses and is directed to the provision of an improved construction for such fuses. .The object of the invention is to produce a novel form of fuse which is of simple construction, the parts of which may be manufactured at very low cost, which permits of renewing a burned-out fuse with great facility and in which the end caps on the ends of thel tube of insulating material are gripped tightly to the ends of the tube by expanding within them the portions of the tube which they inclose.

A fuse constructed inV accordance with the invention consists of a tube of fiber or other insulating material the ends of which are provided with dove-tail slots; in each of these slots is a metallic plate, the sides of which are preferably inclined to correspond to the side walls of the slots in the insulating tube. The distinguishing characteristic of the fuse is that by drawing together the plate and the end cap at each end of the fuse, as by means of suitably arranged screws, the end of the fuse-wire is gripped. between the plate and the end cap and at the same time the movement of the plate in its slot toward the end cap results in expansion of the portions of the insulating tube on opposite sides of the slot in the end of the tube within the end cap so that they bind the end cap tightly upon the tube.

A construction constituting an embodiment of the present invention is illustrated in the accompanying drawing. In this drawing, Figure 1 is a central longitudinal section of the fuse; Fig. 2 is a similar view, the plane of the section being at right angles to the plane of Fig. 1; Fig. 3 is a transverse section on line 3-3 of Fig. 2; Fig. 4 is an elevation of the insulating tube, and Fig. 5 is a lperspective view of the plate which fits within the slot in the endof the tube.

'Referring to theseA drawings,the tube of Specification of Letters Patent.

Serial No. 299,519.

insulating material which constitutes the casing of the fuse, is indicated at 6 In each of its ends is a dove-tail slot, the side walls of which converge toward the end of the tube. The preferred shape of this slot is indicated clearly in Figs. 1 and t. The ends of the portions of tube 6 lying on opposite sides of the slot appear in Fig. 3.

In the slot in each end of the tube 6 is a plate. 7, preferably of the construction shown in Fig. 5. The plate is rectangular, it is of less thickness than the depth of the dove-tail slot in which it lies, and the opposite sides of the plate are inclined as shown at 8, the inclinationl corresponding to the inclination of the side walls of the dove-tail slots in the tube 6. In one end of the plate 7 is a slot 9, and the plate is provided with two threaded openings 10 on opposite sides of its center line.

The fuse-wire 11 extends through the tube 6 as shown; its ends pass through the slots 9 in the plates 7 at opposite ends of the fuse and are bent over so as to extend along the faces of the plate 7 as indicated in Figs. 2 and 3.

0n each end of the tube 6 is an end-cap 12 provided with two openings on opposite sides of its center line prositioned to correspond with the openings 10 in the plate 7 rIlle interior surface of the end portion of each of the end caps is adapted to bear against the end of the tube 6, that is, against the ends of the portions of tube 6 lying on opposite sides of the dove-tail slot. Screws 13 pass through the openings in the end cap 12 and enter the threaded openings 10 in the plate 7. As these screws are tightened up, the plate 7 is drawn outwardly toward the adjacent end cap and in doing so it grips the end of the fuse-wire between the plate and the end cap so as to hold the fuse-wire iirmly and at the same time make good electrical connection thereto; furthermore, as the plate 7 moves outwardly in response to tightening of the screws 13, its inclined side walls act upon the inclined side walls of the portions of tube 6 on opposite sides of the slot to expand them. This expansion of these portions of the end of tube 6 carries them into hard contact with the interior surface of the end cap 12 with' the result that the end cap is gripped firmly to the tube 6. During this operation of tigntening the screws 13, the lend cap 12 is braced against Patented Mar. 30, 1920.

the end of tube 6 as the interior of the end cap bears against the end wall of tube 6 and the plate 7 is moved bodily toward the end oi the end cap to eiliect the gripping of the fuse-wire and the expansion ot the end of tube 6 into gripping relation to the end cap.

Each of the end caps l2 may have a switch blade le secured thereto for cooperation with the clips of a switch, though, of course, such blades Il would be omitted ii the fuse were of the type in which the switch clips cooperate directly with the walls of the end caps l2.

It will be noted that the construction is such that no special precaution is necessary in assembling the parts of the fuse to insure that the two blades I4 will lie in the same plane. rEhese blades are secured rigidly to the end caps and the end caps must be positioned accurately with reference to the axis of the Jfuse in order to bring the screw holes in the end caps into accurate registery with the screw holes in the plates Tgthe plates 7 are, in turn, positioned accurately with respect to the aXis of the fuse by the walls of the slots in the tube 6.

While I have illustrated and described the construction which I prefer to employ and which I consider the best embodiment of my invention, I wish it understood that the invention may be employed in different constructions and I aim to cover such modilied constructions by the terms of the appended claims. The essentials oi" utilization of the invention are that the end-caps shall coperate directly with the ends of the insulating tube 6 so as to be braced thereon; that the plates 7 shall be movable relatively to the tube 6 towaid and away from the ends of the end-caps; and that the cooperating surfaces of the side walls of the plates and the walls of the slots in the tube 6 shall be such that when the plates are so moved, they will cause expansion of portions et the tube 6 with the result that the end-caps will be gripped interiorly and held securely. Such a construction permits of ready renewal of the fuse-wire when the fuse has been burned out, the renewal requiring` but a few moments and no tools other than a screwdriver. Furthermore, the construction is one which permits et manufacture at very low cost as the number o' parts employed is small and the operations incident to manufacturing and assemliling are simple; it will be appreciated that a considerable number of tubes G may be slotted simultaneously alter gripping them in position in alinement on a suitable machine and also that the plates 7 may be cut from a metal strip after the latter has been suitably shaped.

The construction described above and illustrated in the accompanying drawings is that which I prefer to employ, but I wish it understood that the invention may be einbodied in many other constructions. .Iii the form in which the invention is embodied as above described, the movement of the plates bodily relatively to the length of the insulating tube and toward the ends of the end-caps is utilized for two purposes, first, for the purpose of gripping the inse-wire to make good electrical and mechanical connection to it, and second, for the purpose of expanding the end portions el the tube to cause them to grip the inclosing end-caps. It is not essential that this bodily movement of the plates be employed for botlrot these purposes and when the fuse-wire is in the form of a iat strip instead of a round wire, it is preferable to eii'ect the mechanical and electrical connection to the ends of the fusewire in some way other than by resorting to the bodily movement of the plates relatively to the tube. In that case, the movement of the plates is employed for the sole purpose oit expanding the ends oi3 the tube to grip the end-caps.

All such modifications of the construction en'ibodying the present invention I consider to be within the scope of the invention and I aim to cover them by the terms of the claims appended hereto.

l claim:

l. A fuse comprising the combination of a tube of insulating material having dovetail slots in its ends, plates located in the slots iii the tube, end caps upon the tube bearing directly against the ends of the tube, a fuse-wire passing through the tube and having its ends lying between the plates and the end caps, and means for drawing the plates bodily toward the end caps to grip the ends of the fuse-wire between the plates and the end caps and to expand the ends of the tube into the end caps by the cooperation of the plates with the side walls of the dove-tail slots in the tube as the plates are moved toward the end caps.

2. In a fuse, a tube of insulating material having a dove-tail slot across its end, a metallic plate located in the slot and of less thickness than the depth of the slot, said plate having its sides inclined to correspond to the side walls of the dovetail slot and having a slot in one oi its walls, a fuse-wire extending through the slot in the plate and having its end bent to extend along the plate, an end cap on the tube bearing directly against the end of the tube on opp0- site sides of the slot and two screws passing through the end of the end-cap and on opposite sides of the end of the fuseswire and entering threaded holes in the said plate.

3. A fuse comprising the combination of a tube of insulating` material having dovetail slots in its ends, plates located in the slots in the tube, end-caps upon the tube bearing directly against the ends of the tube, a fL1se-Wi1e within the tube, means for making electrica] connection to the fusewire and means for drawing the plates bodily toward the end caps to expand the ends of the tube into the end caps by the coperation of the plates with the side Walls of the idove-tail slots in the tube as the plates are moved toward the end caps.

4. In a fuse, a tube o'. insulating material having a dove-tail slot across its end, a metallic plate located in the slot and of less thickness than the depth of the slot,

said plate having its sides inclined to correspond to the side Walls of the dove-tail slot, an end-cap on the tube bearing directly against the end of the tube on opposite sides of the slot, means passing through the end of the end-cap and coacting with the said plate for moving the plate bodily toward the end of the end-cap and a fuse Within the' tube electrically connected to the end-cap.

In testimony whereof I affix my signature.

ARCHIE W. STEELE. 

